As set out in the above referenced applications/patents, the Applicant has spent a substantial amount of time and effort in developing printheads that incorporate micro electromechanical system (MEMS)—based components to achieve the ejection of ink necessary for printing.
As a result of the Applicant's research and development, the Applicant has been able to develop printheads having one or more printhead chips that together incorporate up to 84 000 nozzle arrangements. The Applicant has also developed suitable processor technology that is capable of controlling operation of such printheads. In particular, the processor technology and the printheads are capable of cooperating to generate resolutions of 1600 dpi and higher in some cases. Examples of suitable processor technology are provided in the above referenced patent applications/patents.
Common to most of the printhead chips that the Applicant has developed is a component that moves with respect to a substrate to eject ink from a nozzle chamber. This component can be in the form of an ink-ejecting member that is displaceable in a nozzle chamber to eject the ink from the nozzle chamber.
A particular difficulty that the Applicant has been faced with is to achieve a suitable interface between a prime mover in the form of an actuator and the moving component. This interface is required to permit the moving component to be displaced in the nozzle chamber and to inhibit leakage of ink from the nozzle chamber.
As set out in the above referenced patents/patent applications, the printhead chip is manufactured using integrated circuit fabrication techniques. This is the usual manner in which MEMS-based devices are fabricated. Such forms of fabrication are subject to constraints since they involve successive deposition and etching techniques. It follows that MEMS-based devices are usually formed in layers and that components having relatively complex shapes are difficult and expensive to fabricate.
In FIG. 1, reference numeral 10 generally indicates part of a nozzle arrangement of a printhead chip. The part 10 shown illustrates an actuator 12 and an ink-ejecting member 14. The actuator 12 includes an elongate actuator arm 16 that extends from an anchor 18. The actuator arm 16 is configured so that, when it receives a drive signal, the actuator arm 16 bends towards a substrate 20 as indicated by an arrow 22. A connecting formation 24 is interposed between the actuator arm 16 and the ink-ejecting member 14. Thus, when the actuator arm 16 is bent towards the substrate 20, the ink-ejecting member 14 is displaced in the direction of an arrow 26 to eject ink from the nozzle chamber.
It would be intuitive simply to use the arrangement 10 together with a suitable sealing structure to achieve effective ink ejection and sealing. The reason for this is that it would appear that the actuator arm 16, the connecting formation 24 and the ink-ejecting member 14 could be in the form of a unitary structure. However, the Applicant has found that it is not possible to achieve a working configuration as shown by using MEMS-based fabrication techniques. In particular, it has been found by the Applicant that such a unitary structure does not lend itself to such fabrication techniques.
It follows that the Applicant has been led to conceive the present invention.